Single row deep groove ball bearings with filling slots

Deep groove ball bearing with filling slots
Single row deep groove ball bearings with filling slots have a filling slot in both the inner and outer rings (fig. 1) to accommodate more balls than standard deep groove ball bearings.

Filling slot bearings have a higher radial load carrying capacity than bearings without filling slots, but their axial load carrying capacity is limited. They are also unable to operate at the same high speeds as bearings without filling slots.

Deep groove ball bearings with filling slots are available open or with shields on one or both sides. They are also available with or without a snap ring groove. Open bearings that are also available with shields may have recesses in the outer ring (fig. 2).

Large size deep groove ball bearings with filling slots, without cage, are available on request.

Shielded bearings

Details regarding the suitability of shields under various operating conditions are listed in table 1. However, these guidelines cannot substitute for testing a shield in its application. For additional information, refer to Integral sealing.

Shields (designation suffix Z, fig. 3)

  • are primarily intended for applications where the inner ring rotates
  • are fitted in the outer ring and form a narrow gap with the inner ring
  • are made of sheet steel
  • are either available with or without a small extension in the shield bore
Greases for shielded bearings

Bearings shielded on both sides are lubricated for the life of the bearing and are virtually maintenance-free. They are filled with high temperature grease GJN as standard.

On request, bearings can be supplied with the following special greases:
  • wide temperature range grease HT or WT
  • wide temperature range and low-noise grease LHT23
  • low temperature grease LT

The technical specifications of the various greases are listed in table 2.

Grease life for capped bearings

  • is presented as L10, i.e. the time period at the end of which 90% of the bearings are still reliably lubricated (diagram 1)
  • depends on:
    • the operating temperature
    • the speed factor
    • grease performance factor (GPF) (table 2)
The indicated grease life is valid for this combination of operating conditions:
  • horizontal shaft
  • inner ring rotation
  • light load (P ≤ 0,05 C)
  • operating temperature within the green temperature zone of the grease (table 2)
  • stationary machine
  • low vibration levels

Where the operating conditions differ as described below, the grease life obtained from the diagrams has to be adjusted:

  • vertical shafts → 50% of the obtained value
  • heavier loads (P > 0,05 C) →  apply reduction factor (table 3)
When capped bearings must operate under certain extreme conditions, such as very high speeds or high temperatures, grease may appear on the capping diameter. For bearing arrangements where this would be detrimental, appropriate actions could be taken. For additional information, contact the SKF application engineering service.
Bearings with a snap ring groove
  • can simplify the design of an arrangement
    • by locating the bearing axially in the housing by a snap ring (fig. 5)
    • by saving space
    • by significantly reducing mounting time.

Appropriate snap rings are shown in the product table, along with their designation and dimensions.

The following variants are available (fig. 6):

  • open bearings with a snap ring groove only (designation suffix N)
  • open bearings with a snap ring (designation suffix NR)
  • bearings with a snap ring and a shield on the opposite side (designation suffix ZNR)
  • bearings with a snap ring and a shield on the same side (designation suffix ZNBR)
  • bearings with a snap ring and a shield on both sides (designation suffix 2ZNR)

SKF single row deep groove ball bearings with filling slots are fitted with a riveted, ball centred stamped steel cage (no designation suffix, fig. 7).

For additional information about the suitability of cages, refer to Cages.

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